Fractured bones are among the most common orthopedic problem; about 6.8 million come to medical attention each year in the United States. Degenerative disc disease resulting in spine fusions has increased significantly and now represents approximately ½ million surgeries annually. The implantation of internal fixation or fusion devices can often be traumatic. If insufficient stabilization or incorrect anatomical alignment occurs, then revision surgery or on-going pain may be experienced by the patient.
There is a need for minimally invasive fracture fixation and spine fusion devices that can provide adequate stability through the use of screws and barbs, while maintaining a natural anatomical alignment during the healing process. If bone growth material is used, then the implant should limit the migration of this material from the fracture or fusion site.
Intramedullary nail devices using temperature effect to insert and fix a device in a bone are disclosed in U.S. Patent Application Publication No. 2010/0241120 to Bledsoe and U.S. Pat. No. 7,695,471 to Cheung et al. The Bledsoe device allows coolant to pass through the implant and into the body via the fracture, which can potentially flush away osteoblast. Osteoblast is believed to promote or accelerate the healing process and by flushing it away there may be a detrimental impact to the healing process. Cheung et al includes bone fixation without using other fastening elements but does not provide a method for maintaining the device in a chilled martensitic phase during implantation.
Minimally invasive interbody spine fusion devices that are introduced in a relatively straight configuration and form a curved configuration within the disc space have been disclosed. One generalized patent to limit the movement of flowable material introduced into or between tissue layers of the human spine U.S. patent application Ser. No. 07/666,227 Benvenue Medical, Inc. (Inventor, Laurent Schaller) The Schaller device prevents or substantially limits the movement of flowable material into vertebral material. However this device does not define any means for mechanical fixation.
In U.S. Pat. No. 8,206,423 Siegal et al has devised a device that utilizes hinges to allow deflection of each segment relative to adjacent segment, the device has a physical geometry which has an elongated element in the fully flexed state and a predefined curved configuration. However, this device defines an external method for delivery of osteogenic material.
Other attempts such as U.S. Pat. No. 8,162,942 focus on fixation barbs and other partial solutions, but have limited applicability and still fail to provide a truly minimally invasive approach, due to the device requiring installation through the joint surface which can result in long term degeneration of the joint surface. All previous attempts have failed to provide a complete solution, but have instead addressed only minimally invasive fixation, anatomical alignment, or the containment of bone growth material, and not all three. Solutions have been long sought but prior developments have not taught or suggested any solutions, and thus, solutions to these problems have long eluded those skilled in the art.